Research at UTHealth confirms strategy to treat retinopathy of prematurity

9:17 April 12, 2010

HOUSTON – Through a strategy developed by scientists at The University of Texas Health Science Center at Houston (UTHealth), doctors can identify premature infants who are most likely to benefit from early treatment to protect against a potentially blinding condition called retinopathy of prematurity (ROP).

The strategy results in better vision for many children, according to long-term results of the Early Treatment for Retinopathy of Prematurity (ETROP) study. Results are published in the April 12th online issue of the Archives of Ophthalmology, a journal of the American Medical Association.

Results of the research, supported by the National Eye Institute (NEI), which is part of the National Institutes of Health, confirm that the visual benefits of early treatment for selected infants continue through age 6.

“We are very excited with these findings because they offer even more hope to families whose infants develop ROP,” said Robert J. Hardy, Ph.D., director of the ETROP study coordinating center and professor of biostatistics at The University of Texas School of Public Health, part of UTHealth. “Doctors now have a better strategy to use at the crib side to monitor these infants and treat their ROP at the most opportune time to improve vision.”

ROP can develop in both eyes of an infant, and it is one of the most common causes of vision loss in children. According to the NEI, approximately 15,000 premature infants are affected by ROP each year. Infants born weighing 2.75 pounds or less and born before 31 weeks gestation are at greatest risk for being diagnosed with ROP. Nearly 90 percent of infants diagnosed with ROP have a mild form that does not require treatment. However, infants diagnosed with a more severe form can develop lifelong visual impairment including blindness.

During a woman’s pregnancy, blood vessels in the eyes of the fetus gradually grow to supply oxygen and nutrients to the retina. However, blood vessels in premature newborns may stop growing before reaching the edge of the retina. This can cause the development of abnormal, fragile blood vessels and retinal tissue at the edges of the normal tissue and can potentially cause scars that pull on the retina. The main cause of visual impairment and blindness in ROP is retinal detachment. According to researchers, the most effective treatments to slow or stop the growth of abnormal blood vessels are laser therapy or cryotherapy.

In 2003, the first phase of the ETROP study found that early identification and treatment of at-risk infants improved their vision and retinal health after nine months. Doctors identified infants who could benefit from early treatment by finding certain eye characteristics, including the appearance and location of blood vessels. This phase of the ETROP study followed the same 370 children through 6 years of age. Researchers examined the vision and development of their eyes and confirmed the study’s early identification recommendations.

Type 1 ROP disease, which puts children at higher risk for blindness, is classified by dilated or twisted blood vessels in the retina and substantial growth of new blood vessels. Seventy-five percent of the early-treated Type 1 eyes were spared legal blindness, compared with 67 percent of Type 1 eyes that received conventional management and treatment. Eyes with Type 2 ROP, classified as having a more moderate amount of new blood vessel growth, did not benefit from early treatment. Of the Type 2 eyes that were carefully monitored for disease progression following a standard protocol, more than half of these eyes improved without treatment.

“While the treatments that are currently available have been shown to be very effective, the ETROP study has identified which infants should be treated and the proper timing for the treatment,” said Hardy.

According to Hardy, not all eyes selected for early treatment do well and additional research is needed to identify better methods for the prevention and treatment of severe ROP.

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